Apparatus for starting and regulating electric discharge lamps



Oct. 2, 1934. I

' c. G. FOUND APPARATUS FOR STARTING AND REGULATING ELECTRIC DiSCHARGE LAMPS Filed Ju'ne 7, 1953 Fig.2.

PHASE OOIVTIMLLER ,His Attorne g.

Patented Oct. 2, 1 934 PATENT OFFICE APPARATUS FOR STARTING AND REGULAT- ING ELECTRIC DISCHARGE LAIVIPS Clifton G. Found, Schenectady, N. General Electric Company, a

New York Y., assignor to corporation of Application June 7, 1933, Serial No. 674,659

11 Claims. (01. 176-124) voltage at which they will operate after being started. One object of my invention is to provide an improved discharge lamp of this form together with apparatus for starting it which is simple in construction, whose operation is not dependentupon the cooperation of relatively start of its own accord moving parts, and which is adapted for use on low voltage lighting circuits. Another object of my invention is to provide improved apparatus for regulating the amount of light produced by such discharge lamps.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a diagram illustrating one form of my invention; and Fig. 2 is a diagram illustrating a modification.

' In the drawing, 1 represents an electric discharge lamp of tubular form, sometimes called a positive column lamp, comprising the evacuated envelope 2, for example a round tube of glass or quartz, having the anode 3 at its upper end and having the cathode 4 in an enlargement or bulb 5 at its lower end. The cathode 4 may be a hot cathode or a cold cathode such as a mercury pool but preferably it is a hot cathode and is shown provided with a heater which may be of any well known form, the source of heating current not being shown. In accordance with the character of the light which the discharge lamp is to give the envelope may contain a small quantity of mercury or sodium vapor, or of neon, krypton, or other gases, or mixtures thereof. Numbers 6 and '7 represent the constant potential source of current supply for the lamp which source may be either direct or alternating. Since an electric discharge lamp has a negative volt-ampere characteristic it is necessary when such a lamp is operated from a constant potential circuit to employ a controlling impedance in series therewith to prevent the current taken by the lamp from rising to a dangerously high value. In the drawing, I have shown such an impedance as comprising the reactor 9 and resistor 10. I

A lamp such as that so far described will not merely by being supplied by a voltagewhich is sufficient to cause the lamp to continue to operate after being started for that voltage is not suflicient to cause the electrons produced by the hot cathode to travel up the tubular body portion of the lamp to the anode. This is due to the high ratio of the length of the tubular body portion of the lamp to the diameter thereof.

'1 shall now-describe the means which I have provided for causing the lamp to be self-starting. At a point in. the tubular body portion intermediate the anode and cathode I have provided tlie auxiliary anode 12, shown in the form of a ring mounted within the tube, and on the reactor 9 I provide the auxiliary winding 13 comprising a few turns of wire. This winding connects at one end with the auxiliary anode 12 and at the other end connects through the rheostat 14 with conductor 7 of the source of supply. I employ a capacitor 15 and connect one side of it with the auxiliary winding 13 and rheostat 14 and the opposite side with the other conductor 6 of the source of supply. The capacitor 15 thereby is charged by the source of supply through the rheostat 14 and when a discharge occurs in the lamp between the cathode and the auxiliary anode thereof the capacitor discharges through the auxiliary winding 13 of the reactor.

The operation of the apparatus is as follows: If the lamp is supplied from a direct current source the voltage of which is insuflicient of itself to cause the lamp to start, the instant that the supply circuit is closed the capacitor begins to receive a charge through the rheostat 14, the voltage across the capacitor being applied between the cathode 4 and the auxiliary anode 12 of the lamp. The distance between the cathode and the auxiliary anode is so short that a discharge will start therebetween when the voltage across the capacitor has risen to a predetermined value. The space between the auxiliary anode and cathode now becomes highly conductive and the capacitor quickly discharges through this space and the auxiliary winding with a relatively high current. The reactor 9 now functions as a transformer, the auxiliary winding 13 being the primary and by reason of the high ratio of transformation between the two windings thereof the discharge current from the capacitor induces a relatively high voltage impulse in the reactor winding. This voltage impulse applied to the main anode 3 is sumcient to cause the discharge quickly to travel up the tube from the auxiliary anode 12 to the main anode and the lamp is started. The initiation of the discharge up the tube to the main anode also is facilitated by the relatively heavy discharge between auxiliary anode and cathode due to the high current flow from the capacitor. Inasmuch as the applied voltage was assumed to be direct the lamp will continue to operate until the circuit is interrupted, it being noted that by reason of the resistance of the rheostat 14 a small current only can flow to the auxiliary anode from the source 6, 7. It the source of supply is alternating the lamp starts in the manner described above at each positive half cycle of the alterhating current wave, that is, at each half cycle at which the anode 3 is positivewith respect to the cathode.

Where it is desirable to change the intensity of the illumination produced by the lamp when the lamp is operated from an alternating current source, for example, where the light is to be dimmed, such a change may be efiected by varying the rheostat 14. Since this rheostat is connected in series with the capacitor 15 an increase in the resistance offered by rheostat 14 produces a greater delay in the voltage wave across the capacitor and therefore between the auidliary anode and cathode with respect to the voltage applied to the main anode in the well understood manner. Thus, by adjusting the rheostat it to include more resistance the lamp can be caused to start at a later time during each positive half cycle, hence giving less total light. Conversely if the rheostat 14. is adjusted to hiclude less resistance the lamp is caused to start at an earlier point in each positive half cycle, thus giving an increased amount of light.

In the modified form oi my invention illustrated by Fig. 2 which is adapted for use with alternating current only, I employ difierent form of apparatus for producing the desired change in the illumination of the lamp. In this case the leads 6 and 7 connect with source of supply 2% of alternating current and connected also with this source is the input circuit of the phase controller represented at 21 having the phase adjusting handle 24.. This phase controlier may, for example, be like that illustrated at 1-2 in the lilexanderson eaten-t 1,655,937, Jannary ii, The output circuit of phase controller 2i. connects through the resistor 25 with opposite sides of the capacitor 15 whereby the phase oi the voltage wave applied to the capacitor and to the siliary anode with respect to a ed to'the main anode may be varied at will by changing the position of the handle as. The operation of the modified form shown by Fig. 2 similar to that of the fGl'l'li shown in Fig. l, the diiierence being that the illiuninatlon produced by the lamp varied by the adjustment the handle 241. an angular adjustment oi. the handle in one direction will produce a greater delay in the voltage wave applied between the auxiliary anode and cathode with respect to the voltage wave applied between the main anode and'cathode thus dimming the light. Conversely an adjustment of the handle in the opposite direction produces less delay in the one voltage with respect to the othenand hence re erner i cause a discharge to occur between the auxiliary diameter of 2 inches at the bulb. The auxiliary anode was located at a distance of iv; inches from the bulb and the lamp was operated from a volt circuit.

I have chosen the particular embodiments described above as illustrative of my invention and it will be apparent that various other modifications may be made without departing from the spirit and scope of my invention which modifications I aim to cover by the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, an electric discharge lamp having main electrodes and an auxiliary electrode between the main electrodes, means for supplying current to said electrodes and means responsive to a current impulse supplied to said auxiliary electrode for producing a voltage increase between the main electrodes.

2. In combination, an electric discharge lamp 3. In combination, an electric discharge lamb having main electrodes and an auxiliary electrode between the main electrodes, source of current supply connected with said electrodes, an impedance in the connection of the source with the main electrodes and means responsive to as current impulse supplied to said auxiliary electrode for inducing a voltage in said impedance.

4-. In combination, an electric discharge lamp having main electrodes and an auxiliary electrode between the main electrodes, a source or alterhating current supply connected with said electrodes, a reactor in the connection of course with one of the main electrodes m ans re sponsive tc a current impulsesupplied to said auxiliary electrode for inducing a voltage impulse in said reactor-r 5. In combination, an electric discharge lamp having a cathode, a main anode and an awziliary anode therebetween, a source 0:? current supply connected with said cathode main anode, a capacitor having opposite sides connected with the cathodeand the aimiliary anode and means actuated by the discharge current of said capacitor for producing voltage impulse in the connection of said source with said main anode.

c. In combination, an electric discharge lamp having a cathode, a main anode an auxiliary anode thercbetween, a source of alternating cur--- rent supply connected with said cathode. and anodes, a reactor in the connection with the main anode, a capacitor having a discharge circuit connected with the auxiliary anode and the cathode and means responsive to the discharge current of the capacitor for inducing a voltage in said reactor.

7. In combination, an electric discharge lamp having a cathode, a main anode and an auxiliary Bill's anode therebetween, a source of alternating current supply connected with the cathode and main anode, and a reactor in said connection provided with an auxiliary winding, said lamp having the auxiliary anode connected with said source through said winding.

8. In combination, an electric discharge lamp having a cathode, a main anode and an auxiliary voltage waves applied to the main anode.

9. In combination, an electric discharge lamp having a cathode, a main anode and an auxiliary anode therebetween, means for supplying an alternating current voltage to said cathode and main anode, an impedance in circuit with the cathode and main anode, means for supplying a current impulse to said auxiliary anode and cathode at each cycle of the supply voltage, means responsive to said impulses for inducing a voltage wave in said impedance and means for delaying the induced voltage wave with respect to the voltage wave supplied.

10. In combination, an electric discharge lamp having a cathode, a mainanode and an auxiliary anode therebetween, means for supplying an alternating current to said cathode and anodes, a reactor in circuit with the cathode and main anode, a capacitor having a discharge circuit connected with said auxiliary anode and cathode, means in said discharge circuit for inducing a voltage impulse inv said reactor and means for adjusting the phase relation between the discharge irom the auxiliary anode and the voltage wave of the current supplied.

11. In combination, an electric discharge lamp having a cathode and a main anode, a source of alternating current supply connected with said cathode and anode, a reactor in said connection provided with an auxiliary win .capacitor arranged source, said lamp having an auxiliary anode adjacent the cathode and a circuit connection between the auxiliary anode and the capacitor through the auxiliary winding.

CLJF'ION G. FOUND.

and ato be charged from said 

